The present disclosure relates to the subject matter disclosed in PCT application No. PCT/EP01/14918 of Dec. 18, 2001, which is incorporated herein by reference in its entirety and for all purposes.
The invention relates to a compressor for refrigerant, comprising a housing, a scroll compressor, which is disposed in the housing and has a first compressor body, which is disposed in a stationary position in the housing, and a second compressor body, which can move relative to the first compressor body, each of these bodies having a base and respective first and second scroll ribs, which are formed, for example, in the form of an involute to a circle and/or an arc of a circle, which rise above the respective base and engage in one another in such a way that, during compression of the refrigerant, the second compressor body can be moved along an orbital path about a center axis with respect to the first compressor body, and a drive for the second compressor body, having a drive motor.
Compressors of this type are known from the prior art, for example DE 100 99 10 460.
In compressors of this type, there is a need to achieve the highest possible efficiency, in particular the lowest possible leakage, during compression of the refrigerant.
In the case of a compressor of the type described in the introduction, this object is achieved, in accordance with the invention, by the fact that the refrigerant which is to be compressed by the scroll compressor can wash around the two compressor bodies in the region of their rear side, which is remote from the scroll ribs, so that the compressor bodies can be cooled.
The advantage of the inventive solution is considered to be that it makes it possible for both compressor bodies to be cooled in the same way and therefore for at least a similar temperature distribution to be achieved in both compressor bodies, so that both compressor bodies have a similar thermal expansion, and therefore the low but not insignificant leakage which can be achieved by means of high manufacturing precision is not adversely affected by uneven temperature distributions and therefore different levels of thermal expansion, so that overall the efficiency of the scroll compressor is reduced as a result.
In this context, it is particularly advantageous if the refrigerant which is to be compressed can wash around the second compressor body in the region of the rear side, which is disposed opposite the second scroll rib, radially outside its driver receiving part, since refrigerant washing around the compressor body on its rear side ensures that this body is effectively cooled, and in particular cooling is ensured as close as possible to the regions of the compressor body in which most heat is introduced.
Furthermore, it is particularly advantageous if the refrigerant which is to be compressed can wash around the first compressor body in the region of a rear side, which is remote from the first scroll rib.
In this case too, it is particularly advantageous for the compressor body to be cooled via its rear side, in order once again to provide cooling as close as possible to the regions of the compressor body in which considerable amounts of heat are introduced, in particular through heated compressed refrigerant.
In order also to enable the scroll ribs to be cooled as efficiently as possible via the rear side of the compressor body, it is preferably provided that the rear surface of the respective compressor body is formed directly by a base which carries the respective scroll rib, so that the scroll ribs which are connected to the respective base are also cooled as efficiently as possible.
In particular, with a view to the most efficient conduction of heat possible, it is particularly advantageous if the rear side of the compressor body forms the rear side of a unitary part which includes the base and the scroll rib and, in particular in the region of the rear side, does not have any elements which are incorporated in or connected to, for example fitted onto, this part.
To improve the cooling of the compressor bodies still further, it is preferably provided that both compressor bodies can be cooled by the refrigerant which is to be compressed in the region of a peripheral side which is on the outer side with respect to the center axis.
In connection with the explanation of the cooling of the first compressor body in the region of its rear side, it has not been defined in more detail whether cooling takes place substantially over the entire rear side or only in partial regions of the rear side.
In particular, it has also not been specified in further detail to what extent the first compressor body is still fixed via the rear side.
A particularly favorable solution provides that the refrigerant which is to be compressed can wash around the first compressor body in the region of its rear side which lies outside a high-pressure connection.
This provides a particularly large area, namely the area which lies radially outside the high-pressure connection, for cooling of the first compressor body, the high-pressure connection also contributing, in particular at least in part, to fixing the first compressor body in the housing.
A solution which is particularly advantageous in design terms provides that a rear-side cooling chamber, through which the refrigerant which is to be compressed can wash, lies between the rear side of the first compressor body and a partition of the housing, which runs at a spacing from this rear side.
The rear-side cooling chamber may be formed in a very wide variety of ways. A particularly favorable solution provides for the rear-side cooling chamber to surround a mounting receiving part for the first compressor body, so that substantially the rear side of the compressor body, with the exception of the regions in which the mounting receiving part is active, can be cooled via the rear-side cooling chamber.
It is preferable for the mounting receiving part to be formed in such a way that the rear-side cooling chamber runs in the form of a ring around the mounting receiving part for the first compressor body.
In this context, it is particularly suitable if the high-pressure connection for the first compressor body is integrated into the mounting receiving part and therefore passes through this mounting receiving part.
Particularly efficient cooling of the first compressor body is achieved if the mounting receiving part can also be cooled via the rear-side cooling chamber, so that if heat is introduced into the mounting receiving part by the refrigerant emerging under high pressure, the mounting receiving part itself can be directly cooled, in order for this heat to be dissipated.
In connection with the previous explanation of the individual exemplary embodiments, emphasis has been placed primarily on the cooling of the compressor bodies via the rear side. The cooling of the compressor bodies can be improved still further by the fact that the rear-side cooling chamber merges into a peripheral-side cooling chamber which surrounds an outer periphery of the first compressor body.
In this case, it is preferable for the peripheral-side cooling chamber to surround not only the outer periphery of the first compressor body but also the outer periphery of the second compressor body.
A solution which is particularly advantageous in mechanical terms provides that the first compressor body is supported by outer support elements which lie radially outside the scroll ribs with respect to the center axis.
In this case, it is particularly advantageous if the peripheral-side cooling chamber runs around the outer support elements, and therefore cools the first compressor body via the outer support elements, in particular if the outer support elements are formed integrally on the first compressor body.
Thus far, no further statement has been made in connection with the cooling action of the refrigerant which is to be compressed and washes through the rear-side cooling chamber. By way of example, a particularly advantageous exemplary embodiment provides that the temperature of the surface, which borders the refrigerant which is to be compressed in the rear-side cooling chamber, of the first compressor body within an annular region which lies between approximately 50% and approximately 80%, preferably approximately 60% and approximately 70%, of a maximum radius of the scroll ribs is at most 8xc2x0 centigrade, preferably at most 5xc2x0 centigrade, higher than the temperature of the refrigerant which is to be compressed and reaches the second compressor body.
This relation shows that sufficient cooling of the first compressor body is possible even if refrigerant which is to be compressed washes sufficient thoroughly through the rear-side cooling chamber; this washing action may take place as a result of pressure fluctuations, turbulence or convection and does not necessarily require the refrigerant which is to be compressed to flow through the rear-side cooling chamber.
In connection with the above description of the individual exemplary embodiments, no further statements have been made with regard to the order in which the compressor bodies are cooled.
By way of example, a particularly advantageous exemplary embodiment provides that the refrigerant which is to be compressed washes around the second compressor body first of all and then around the first compressor body.
In principle, the refrigerant which is to be compressed could originate from any desired section of a cooling installation. It is particularly advantageous if the refrigerant which is used to cool the compressor bodies is the refrigerant which is to be sucked in by the scroll compressor.
It could be refrigerant which, after it has cooled the compressor bodies, also cools further units. A particularly advantageous embodiment provides that the refrigerant which is to be sucked in cools the compressor bodies substantially immediately before it enters an intake region of the scroll compressor.
This solution is advantageous if only for the reason that the refrigerant which is to be compressed and is to be fed to the scroll compressor in any case, immediately before it enters the intake region, can be used to cool the compressor bodies.
The solutions which have been described thus far have not provided any further details as to how the refrigerant which is to be compressed enters the scroll compressor. A particularly favorable solution provides that the refrigerant which is to be sucked in flows into the intake region of the scroll compressor at least in part from a peripheral side of the scroll compressor between the base of the first compressor body and the base of the second compressor body.
In particular, it is possible for the refrigerant which is to be sucked in to be guided in such a way that it flows into the intake region of the scroll compressor at least partially radially with respect to the center axis between the bases of the compressor bodies.
To achieve particularly efficient cooling of the rear-side cooling chamber, it has proven advantageous if the refrigerant which is to be compressed, at least in the form of a part-stream, flows with forced guidance through the rear-side cooling chamber, so that, as a result of the forced guidance of the part stream, sufficiently intensive washing through the rear-side cooling chamber is ensured under all operating conditions.
This can advantageously be achieved by the fact that the refrigerant which is to be sucked in flows into the intake region of the scroll compressor at least in part from the rear-side cooling chamber through at least one aperture in the base of the first compressor body.
The inevitable result of this is that at least a part stream of the refrigerant which is to be sucked in flows through at least a partial region of the rear-side cooling chamber and therefore the refrigerant which is to be compressed washes with sufficient intensity any regions of the rear-side cooling chamber through which there is no direct flow, as a result of turbulence, pressure fluctuations and/or convection, in order for these regions to be cooled.
An embodiment of the solution according to the invention which is particularly advantageous and in particular operates stably in all operating regions provides that all the refrigerant which is to be sucked in flows into the intake region of the scroll compressor through the rear-side cooling chamber and then through at least one aperture in the base of the first compressor body, so that this forced guidance of the refrigerant which is to be compressed ensures sufficiently intensive washing of the rear-side cooling chamber even at low volumetric flows.
Furthermore, if the refrigerant which is to be compressed is guided in this manner, there is a reduced risk of liquid refrigerant entering the intake region if the first compressor body is disposed above the second compressor body and in particular also above the drive.
In the compressor according to the invention, the drive motor usually also needs to be cooled. It could be cooled separately. However, an advantageous embodiment provides for the refrigerant which is to be compressed to cool the drive motor and the scroll compressor.
In order, in particular, to ensure that no liquid refrigerant enters the scroll compressor itself, in particular when the compressor is being started up, it is preferably provided that the refrigerant which is to be compressed cools the drive motor first of all and then cools the scroll compressor. As a result, it is easy to achieve sufficiently intensive heating of the refrigerant which is to be compressed before it enters the scroll compressor, in order to avoid liquid refrigerant in the scroll compressor.
No more detailed statements have been made concerning the flow through the drive motor. By way of example, an advantageous solution provides for the refrigerant which is to be compressed to cool the drive motor on the rotor side.
In addition or as an alternative to this, there is provision for the refrigerant which is to be compressed to cool the drive motor on the peripheral side.
Furthermore, the compressor according to the invention can be made particularly simple if the refrigerant which is to be compressed first of all flows around the second compressor body in the region of the rear side of the base thereof, in particular radially outside the support body, and then enters the intake region of the scroll compressor, since as a result the refrigerant which flows through the drive motor can be used to cool the second compressor body immediately after the drive motor.
Furthermore, it is preferably provided that the refrigerant which is to be compressed, before entering the intake region, flows around support elements of the scroll compressor which are on the radially outer side with respect to the center axis of the first scroll rib.
In connection with the description given thus far of the individual exemplary embodiments, no further statements have been made as to the sealing of the scroll rib. By way of example, an advantageous embodiment provides for the scroll ribs of one compressor body, on end sides which face the base of the other compressor body, to carry end-side seals which are fitted into grooves.
These end-side seals could be disposed immovably in the grooves. It is particularly advantageous if the end-side seals can move in the grooves, in the direction of the base of the other compressor body.
A particularly suitable embodiment provides that the end-side seals, under the action of the higher pressure in each case in the scroll compressor, can be moved in the direction of the base of in each case the other compressor body.
The end-side seals may be made from different materials. By way of example, it is known from the prior art to form the end-side seals from metal lamellae. A particularly advantageous solution provides for the end-side seals to be made from plastics.
It has proven particularly suitable for the end-side seals to be made from Teflon.
It is preferable to use a TefleR Teflon(copyright) compound comprising approximately 5% to approximately 20% of carbon and other strength-promoting additives.
Furthermore, in the compressor according to the invention it is preferable for a nonreturn valve, which prevents the refrigerant which is under high pressure from flowing back into the scroll compressor, to be associated with the high-pressure outlet.
In this case, it is preferable for the nonreturn valve to be formed in such a way that it has a seal seat which lies in the first compressor body.
An alternative solution provides that the nonreturn valve is disposed in a high-pressure chamber on a side of the partition which lies opposite the first compressor body.
Further features of the invention form the subject matter of the following description and of the drawing illustrating some exemplary embodiments.